白洋淀是华北平原最大的浅水草型湖泊，由于上游水库建设和社会经济用水的增加，近些年入淀水量急剧减少，淀区生态需水难以保证；此外，上游市区、乡镇的大量污水由府河入淀，恶化了水质，更进一步加剧了水资源的短缺。本研究将污染胁迫因素引入生态需水的估算过程中，构建了基于WASP的白洋淀水质模拟模型，设定了不同的污染物源控制水平与生态调水补给的情景组合模式，借助于水质过程模拟，综合确定污染胁迫下的白洋淀生态需水规律；并在此基础上，综合考虑社会、生态、经济等因素，对白洋淀流域水资源进行多目标优化配置，以有效缓解流域生态用水和社会经济用水之间的矛盾，并为浅水草型湖泊生态用水调度提供一定的科学依据。本文的主要研究内容为：（1）基于WASP的白洋淀水质模型的构建与模拟：利用WASP的EURTO模块构建了白洋淀水质模拟模型，模拟了不同污染源控制水平和不同入淀流量情况下白洋淀水体中关键富营养化水质指标变化与分布。通过水质模拟发现，控源和调水，可以在一定程度上缓解水体污染现象，且控源对水质的影响相对较大，因此仅通过调水稀释，不能从本质上解决湖泊水质污染和水资源短缺问题。（2）污染胁迫下白洋淀生态需水量估算：面向不同的管理目标，设置了不同污染源控制水平和入淀流量的系列组合情景方案，通过WASP模拟估算了污染胁迫下的白洋淀生态需水量，获得了不同污染胁迫水平下的白洋淀生态需水规律。研究得出，在污染源削减30%、50%和90%的前提下，白洋淀淀区的年生态需水量分别为3.26×108 m3，3.18×108 m3和2.63×108 m3。（3）面向白洋淀生态需水保障的水资源优化配置：在水资源供需平衡分析的基础上，根据白洋淀区域水源和用水户的关系，建立了面向白洋淀生态需水保障的水资源多目标优化配置模型，采用理想点法对该模型进行求解，得到了2020和2030两个水平年，丰、平、枯等不同水文条件下的白洋淀生态用水配置方案。分析研究结果可以得出，未来枯、平水年白洋淀区域存在不同程度的缺水问题，为保障白洋淀生态用水，很大程度上需借助于跨流域调水。

Baiyangdian, the largest shallow hydrophytes type lake in the North China Plain, has the severe water shortage problem because of the sharp increase of social economic water and sewage discharge. Sustainable management of environmental flows and optimal allocation of water resources are very important to alleviate the water shortage and aquatic ecosystem deterioration. In this paper, using Baiyangdian Lake as a case study, I have developed a water quality model for Baiyangdian Lake based on Water Quality Analysis Simulation Program (WASP, version 7.3), obtained its environmental flows by scenario analysis, and analyzed the water resources optimal allocation for Baiyangdian Watershed.The main contents of research are as follows:(1) The establishment of a water quality model for Baiyangdian Lake: The lake was divided into 13 sub-areas using GIS software. Water-quality processes of each sub-area were simulated by using an eutrophication model based on the WASP 7.3 software. Monitoring data in Baiyangdian Lake were used to calibrate and validate the model. Using the model, water quality simulation was then analyzed in the scenarios with different pollution loads and artificial water release to reveal the relationships between water quality and the two factors. The results revealed that return water such as industrial wastewater and domestic sewage with a large organic load worsened eutrophication, whereas reducing pollutant loads, releasing some water into the lake, or a combination of the two approaches could improve water quality in Baiyangdian Lake.(2) Environmental flows requirements with consideration of water quality: Based on the simulation, a series of scenarios, which combined reducing pollutant loads with releasing water into the lake, were set up to reveal the sustainable environmental flows. The detailed spatial distribution of water quality supplied the important information to support further determination of sustainable environmental flows. The simulated results revealed that the sustainable environmental flows is 3.26×108, 3.18×108, and 2.63×108 m3/a, respectively, for the scenarios with pollutant-loads reductions of 30, 50, and 90%.(3) Optimal allocation of water resources in Baiyangdian Watershed: The water balance of supply and demand was analyzed, and the quantity in 2020 and 2030 were forecasted in Baiyangdian Watershed. And then a multi-objective optimal model for water resources allocation was established. The ideal point method was used to find the optimum solutions of the model. Based above, the optimal allocation schemes of water resources in Baiyangdian Watershed in different hydrological scenerios were obtained, respectively, in 2020, and 2030. Water deficient would be serious in dry, or average years. The maximum water deficient ratio could be 19.68% in 2020, and 18.38% in 2030. According to the results, Baiyangdian Lake had different degree of water shortage in different hydrology conditions, and it should draw support from inter-basin water transfer to satisfy the ecological demand.